LOCATION PETAN                   NV+ID

Established Series
Rev. RAF/TSB/TM/JBF
10/2019

PETAN SERIES

The Petan series consists of shallow over duripan, well drained soils that formed in residuum derived from rhyolite and basalt. Petan soils are on side slopes of hills, plateaus and fan piedmonts and have slopes are 4 to 15 percent. Mean annual precipitation is about 360 mm and the mean annual temperature is about 6 degrees C.

TAXONOMIC CLASS: Clayey-skeletal, smectitic, frigid, shallow Typic Durixerolls

TYPICAL PEDON: Petan extremely stony loam--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with 5 percent gravel, 30 percent cobbles and 10 percent stones.

A1--0 to 8 cm; grayish brown (10YR 5/2) extremely stony loam, very dark grayish brown (10YR 3/2) moist; moderate thick platy structure; soft, very friable, slightly sticky and slightly plastic; common very fine roots; common very fine tubular pores; 10 percent gravel, 25 percent cobbles and 30 percent stones; neutral (pH 7.2); clear smooth boundary. (5 to 10 cm thick)

A2--8 to 15 cm; brown (10YR 5/3) very stony clay loam, dark brown (10YR 3/3) moist; moderate fine granular structure; hard, firm, moderately sticky and moderately plastic; few fine and very fine roots; few very fine tubular pores; 5 percent gravel, 10 percent cobbles, and 25 percent stones; neutral (pH 7.2); abrupt smooth boundary. (5 to 15 cm thick)

Bt1--15 to 25 cm; brown (10YR 5/3) very cobbly clay, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; very hard, very firm, very sticky and very plastic; few very fine roots; many faint clay films on peds; 15 percent gravel and 25 percent cobbles; neutral (pH 7.2); clear smooth boundary. (8 to 13 cm thick)

Bt2--25 to 48 cm; dark yellowish brown (10YR 4/4) very cobbly clay, brown (10YR 4/3) moist; moderate medium prismatic structure that parts to strong medium angular blocky; extremely hard, extremely firm, very sticky and very plastic; many distinct clay films on ped faces; 15 percent gravel and 40 percent cobbles; slightly alkaline (pH 7.4); abrupt smooth boundary. (15 to 23 cm thick)

Bqkm--48 to 50 cm; very pale brown (10YR 8/3) indurated laminae 3 to 13 mm thick over a degrading duripan; massive; extremely hard, extremely firm; strongly effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary. (1 to 8 cm thick)

R--50 cm; basalt

TYPE LOCATION: Owyhee Desert, Elko County, Nevada; approximately 6 miles north of Josephine Reservoir; about 200 feet south and 1,600 feet west of the northeast corner of section 10, T. 47 N., R. 49 E., Mount Diablo Meridian; USGS Hat Peak 7.5 minute topographic quadrangle; latitude 41 degrees 59 minutes 35 seconds N and longitude 116 degrees 28 minutes 16 seconds W; WGS84 Decimal Degrees 41.9930556 latitude, -116.4711111 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Moist in winter and spring, dry from mid July through October; aridic soil moisture regime bordering on xeric.
Mean annual soil temperature: 6 to 8 degrees C.
Thickness of mollic epipedon: 18 to 30 cm, includes the upper part of the Bt horizon.
Depth to base of argillic horizon: 36 to 50 cm.
Depth to duripan: 36 to 50 cm.
Depth to bedrock: 38 to 58 cm.

Particle-size control section - Clay content: 40 to 60 percent.

A horizon
Value: 5 or 6 dry, thin layers with value of 6 dry, when mixed with the upper 7 cm, have dominate value of less than 5.5 dry.
Chroma: 2 or 3.

Bt horizon
Value: 4 through 6 dry, 3 or 4 moist.
Chroma: 3 or 4.
Rock fragments: 35 to 55 percent, mainly cobbles or stones.
Other features: Darker value and chroma in upper Bt horizon.
Reaction: Slightly acid through slightly alkaline.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Petan soils are on side slopes of hills, plateaus and fan piedmonts with a rock core. They formed in residuum derived from rhyolite and basalt with some influence from loess and volcanic ash. Slopes are 4 to 15 percent. Elevations of 1,620 to 1,740 meters. Climate is cool and subhumid with warm, dry summers and cool, moist winters. Mean annual precipitation is 300 to 400 mm, mean annual temperature is 5 to 7 degrees C, and the frost-free season is 70 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bulake and Deunah soils. Bulake and Deunah soils have less than 35 percent rock fragments in the argillic horizon. In addition, Bulake soils lack a duripan and Deunah soils have a duripan deeper than 50 cm.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; medium runoff; moderately low saturated hydraulic conductivity.

USE AND VEGETATION: Livestock grazing and wildlife habitat. Vegetation is mainly low sagebrush, bluebunch wheatgrass, Idaho fescue, and rabbitbrush.

DISTRIBUTION AND EXTENT: North-central Nevada and southwestern Idaho. MLRA 25. Petan soils are of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Elko County, Nevada, Duck Valley Indian Reservation Idaho and Nevada, 1984.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the surface of the soil to a depth of 25 cm (A1, A2 and Bt1 horizons).
Argillic horizon - The zone from about 15 to 48 cm (Bt1 and Bt2 horizons).
Duripan - The zone from about 48 to 50 cm (Bqkm horizon).
Lithic contact - The boundary at 50 cm (R layer).
Particle-size control section - The zone from 15 to 48 cm (Bt1 and Bt2 horizons).

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National Cooperative Soil Survey
U.S.A.